The main weapon system of a modern military tank such as the M60A3 tank is a gun that fires projectiles responsive to the firing command of a human gunner. However, the firing command does not go directly from the gunner to the gun. The firing command is supplied to a fire control system, typically a director-type fire control system, that coordinates the firing command with other information, such as the motion of the gun, the motion of the vehicle, the motion of the target, the range of the target, the type of projectile, environmental conditions, and other information. The fire control system constantly performs and updates the ballistic solution for the potential target. The fire control system typically calculates a desired gun-sight offset in elevation (i.e., how much of an angle above the target the gun should be pointed to hit the target) and the desired gun-sight offset in azimuth (i.e., how much of an angle left or right of the target the gun should be pointed to hit the target). With this information and the constant measurements of the actual gun-to-sight offsets in elevation and azimuth, the fire control system constantly calculates the error values between the desired offsets and the actual offsets. These error values are used to reposition the gun and to determine when the error values are sufficiently close to zero that a shot would be of sufficiently high probability for a hit (alternatively stated, is inside the “coincidence window”).
After receiving the firing command from the gunner and performing the fire-control calculations, the fire control system produces a shoot command that actually fires the gun at the appropriate moment. Thus, the fire control system takes into account many factors that cannot be readily evaluated quickly by the human gunner, while the gunner makes the decisions on target selection and the time at which the firing sequence is started.
In order to evaluate the performance of the fire control system and to train the gunner to work with the fire control system under a wide variety of conditions, the conventional practice is to perform a series of live-fire tests. In these tests, the tank and its crew, including the gunner, are transported to a live-fire range. A statistically significant number of rounds are fired under various conditions, such as the tank standing still, and the tank moving over various surfaces and at various speeds, and under a variety of weather conditions and using a variety of types of ammunition. These live-fire tests are expensive to perform, as the transportation costs and operating costs are high, and the cost of each round fired is typically about $500.
Additionally, the live-fire tests have shortcomings in regard to the results. The accuracy in hitting the target with the projectile depends upon variations in extraneous factors other than the gunner and the tank system, such as the variations in the propulsive and flight properties from projectile to projectile (“ammunition dispersion”), and the wind and the weather (“environmental dispersion”). These factors cannot be maintained constant in a live-fire test series, so that there is always some uncertainty as to whether the statistical results of the live-fire test series reflect the performance of the gunner and the weapon system, or whether the extraneous dispersion factors are the dominant effect.
Various attempts have been made to improve upon the present approach. Motion tracking techniques are used to determine the positions of the gun and the site used by the gunner, but this approach cannot determine the pointing accuracy of the weapon system. Smaller caliber, inexpensive test projectiles may be used, but they are even more subject to the extraneous factors. Tank simulators are employed in early training of tank crews, but do not provide a sufficiently realistic simulation in advanced training of the actual field conditions that the tank crew will experience, such as bouncing, vibration, and noise for the particular tank that the gun crew will use.
There is a need for an approach to evaluating and training gunners, and evaluating the tank weapon system, which is less expensive than the current approach and also is not affected by the extraneous factors. The present invention fulfills this need, and further provides related advantages.